Israel's military operation was continuing in the northern Gaza Strip Sunday, entering its fifth day, as troops were surrounding the Jabalya refugee camp and the town of Beit Hanoun in a wide-scale raid to "end Qassam rocket launchings into Israeli territory".

Israeli soldiers have also surrounded the town of Khan Yunis in the southern Gaza Strip.

So far, the Israeli operation in Gaza Strip has resulted in the deaths of at least 71 Palestinians.

Meanwhile, Israel's Prime Minister Ariel Sharon told Army Radio Saturday night Israel will operate in Gaza until all Palestinian rocket fire against Israeli towns is halted.

While Sharon approved the plan of the operation, he called on his defense minister and top army officers to come up with "new ideas".

"This is a complicated struggle. I have directed the defense minister to do everything possible and to find new methods as the need arises," Sharon said.

Four Palestinians were killed early Sunday when Israeli tanks shelled houses located eastern Jabalya refugee camp, witnesses and Palestinian medical sources said. They told WAFA that Israeli tanks, stationed at al-Sikka street fired two pin shells against houses located in block "4", killing four and wounding others. Medics in the camp confirmed that Ramy Qudaas, Misbah al-Ranteesy, Yasser Ghbeez, 20, and Mohammed al-Shrafy were killed in the attack.

Israel said the dead were Hamas and Islamic Jihad members. According to the Israeli military, soldiers opened fire when they saw the men "planting a bomb".